Photocapacitor

ABSTRACT

A photocapacitor is provided. The photocapacitor includes: a perovskite solar cell and a supercapacitor attached to the perovskite solar cell. The supercapacitor includes a first carbon nanotube structure. The perovskite solar cell includes third carbon nanotube structure. The first carbon nanotube structure is directly contacted with the third carbon nanotube structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims all benefits accruing under 35 U.S.C. § 119 from China Patent Application No. 201710938137.5, filed on Sep. 30, 2017, in the China Intellectual Property Office, the contents of which are hereby incorporated by reference. The application is also related to co-pending applications entitled, “METHOD FOR MAKING PHOTOCAPACITOR”, concurrently filed (Atty. Docket No. US71889).

FIELD

The present disclosure relates to the field of energy storage, and more particularly to solar energy storage.

BACKGROUND

Perovskite solar cell is a type of solar cell which includes a perovskite structured compound. Perovskite solar cells have become commercially attractive with higher efficiencies and low production costs. However, the voltage output of the perovskite solar cell changes as the sunlight changes, as a result the perovskite solar cell is not suitable to power portable electronics.

Therefore, there is room for improvement in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a flow diagram of one embodiment of a method for making photocapacitor.

FIG. 2 is a flow diagram of one embodiment of a method for making perovskite solar cells.

FIG. 3 is a schematic view of one embodiment of a photocapacitor.

FIG. 4 is voltage output performances of a perovskite solar cell under different illumination conditions.

FIG. 5 is voltage output performances of a photocapacitor under different illumination conditions.

DETAILED DESCRIPTION

It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. The drawings are not necessarily to scale, and the proportions of certain parts may be exaggerated to be better illustrate details and features. The description is not to be considered as limiting the scope of the embodiments described herein.

Several definitions that apply throughout this disclosure will now be presented.

The connection can be such that the objects are permanently connected or releasably connected. The term “outside” refers to a region that is beyond the outermost confines of a physical object. The term “inside” indicates that at least a portion of a region is partially contained within a boundary formed by the object. The term “substantially” is defined to essentially conforming to the particular dimension, shape or other word that substantially modifies, such that the component need not be exact. For example, substantially cylindrical means that the object resembles a cylinder, but can have one or more deviations from a true cylinder. The term “comprising” means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in a so-described combination, group, series and the like.

FIG. 1 shows an embodiment of a method for making photocapacitor. The method includes, at least the following steps:

S1, preparing a perovskite solar cell 100 which includes an absorbing layer 140 and a cell packaging structure 160; wherein the absorbing layer 140 includes a third carbon nanotube structure 141 and a perovskite structure 143, the third carbon nanotube structure 141 is a layered structure including a first surface 1411 and a second surface 1412 opposite the first surface, the first surface 1411 is directly contacted with the perovskite structure 143 and the second surface 1412 is directly contacted with the cell packaging structure 160; a surface of the cell packaging structure 160 away from the absorbing layer 140 is defined as a second solar cell surface 1002;

S2, preparing a first supercapacitor electrode 200 a which includes a first electrode structure 210 a and a second electrode structure 230 a stacked with each other, the first electrode structure 210 a includes a first carbon nanotube structure 211 a comprising a plurality of first carbon nanotubes, adjacent first carbon nanotubes form a plurality of first micropores, some of the first micropores are filled with a first material 213 a; a surface of the first electrode structure 210 a away from the second electrode structure 230 a is defined as an first electrode surface 2001 a;

S3, attaching the first supercapacitor electrode 200 a onto the perovskite solar cell 100, wherein the second solar cell surface 1002 is directly contacted with the first electrode surface 2001 a;

S4, dissolving a portion of the cell packaging structure 160 and the first material 213 a until the third carbon nanotube structure 141 and the first carbon nanotube structure 211 a in direct contact with each other; and

S5, preparing a second supercapacitor electrode 200 b opposite to the first supercapacitor electrode 200 a.

In step S1, the perovskite structure 143 can be made of perovskite material, such as MAPbI₃. The perovskite solar cell 100 can further include conductive glass layer 110 and a blocking layer 130. The conductive glass layer 110, the blocking layer 130, and the absorbing layer 140 are planar structures and stacked with each other. The blocking layer 130 is sandwiched between the conductive glass layer 110 and the absorbing layer 140. A surface of the conductive glass layer 110 away from the absorbing layer 140 is defined as a first solar cell surface 1001, and a surface of the cell packaging structure 160 spaced away from the absorbing layer 140 is defined as a second solar cell surface 1002.

FIG. 2 shows an embodiment of a method for making a perovskite solar cell 100. The method includes, at least the following steps:

S11, providing a conductive glass layer 110 with a conductive surface 111;

S12, depositing a blocking layer 130 onto the conductive surface 111;

S13, locating an absorbing layer 140 onto the blocking layer 130 to form a perovskite solar cell preform, wherein the absorbing layer 140 includes a third carbon nanotube structure 141; and

S14, depositing a cell packaging material on surfaces of blocking layer 130 and absorbing layer 140 to form a cell packaging structure 160.

In step S11, the conductive glass layer 110 can be ultrasonically cleaned in detergent, deionized water, acetone and isopropanol (IPA) in sequence, dried with compressed nitrogen. In one embodiment, the conductive glass layer 110 is fluorine-doped tin oxide (FTO) glass.

In step S12, the blocking layer 130 can transport electrons and block holes. In one embodiment, the material of the blocking layer 130 is titanium dioxide (TiO₂), a compact titanium TiO₂ blocking layer is deposited by spin-coating 90 μL of acidic titanium isopropoxide/ethanol solution (70 μL of titanium isopropoxide, 7 μL of 2 M HCl, 1 mL of ethanol) onto the FTO substrate at a speed of 2000 rpm for 50 s, then the FTO substrate is dried at 150° C. for 30 min and annealed at 500° C. for 30 min.

In step S13, the absorbing layer 140 is prepared by depositing a BX₂ (a halide of metal B) film onto the blocking layer 130, depositing a carbon nanotube film onto the BX₂ film, and coating an AX (halogenated salt of organic amino A) solution onto the carbon nanotube film and heating.

In one embodiment, BX₂ is PbI₂, AX is CH₃NH₃I solution, and the carbon nanotube is multi-walled carbon nanotube (MWCNT). A PbI₂ film is deposited onto the blocking layer 130 by spin-coating 90 μL of PbI₂/N, N-Dimethylformamide solution (500 mg/mL) at a speed of 2000 rpm for 50 s. A MWCNT film is deposited onto the PbI₂ film by drop-casting 120 μL of MWCNT/chlorobenzene solution (10 mg/mL). 120 μL of CH₃NH₃/IPA solution (10 mg/mL) is dropped onto the MWCNT film for 3 min, dried by spinning at 2000 rpm for 50 s and heated in an environment of 100° C. for 30 min to obtain an absorbing layer 140 including a third carbon nanotube structure 141 and a perovskite structure 143 made of MAPbI₃.

The third carbon nanotube structure 141 is a layered structure which includes a first surface 1411 and a second surface 1412 opposite to the first surface 1411. The first surface 1411 is directly contacted with the perovskite material (e.g. MAPbI₃), and the second surface 1412 is exposed to the air.

The third carbon nanotube structure 141 includes a plurality of third carbon nanotubes joined by van der Waals attractive force therebetween and forming a free-standing film network. Adjacent third carbon nanotubes form a plurality of third micropores. Some of the third micropores are filled with the perovskite material.

In step S14, parts of the micropores of the third carbon nanotube structure 141 are filled with the cell packaging material. The cell packaging material can be Polymethyl methacrylate (PMMA). In one embodiment, a PMMA film is deposited onto the perovskite solar cell preform by spin-coating 0.5 mL of PMMA/toluene solution (100 mg/mL) at a speed of 3000 rpm for 50 s, dried at room temperature.

In step S2, both the first electrode structure 210 a and the second electrode structure 230 a are planar structures and stacked with each other. A surface of the first electrode structure 210 a opposite to the second electrode structure 230 a is defined as a first electrode surface 2001 a, and a surface of the second electrode structure 230 a opposite to the first electrode structure 210 a is defined as a second electrode surface 2002 a.

The first electrode structure 210 a includes a first carbon nanotube structure 211 a. The first carbon nanotube film 211 a includes a plurality of first carbon nanotubes joined by van der Waals attractive force therebetween. Adjacent first carbon nanotubes form a plurality of first micropores. Some of the first micropores are filled with a first material 213 a. The first material 213 a can be PMMA.

The second electrode structure 230 a includes a second carbon nanotube structure 231 a. The second carbon nanotube structure 231 a includes a plurality of polymer coated active carbon nanotubes joined by van der Waals attractive force therebetween. Adjacent polymer coated active carbon nanotubes form a plurality of second micropores. Some of the second micropores are filled with a second material 233 a. The second material 233 a can be supercapacitor electrolytes.

In one embodiment, a method for making the first supercapacitor electrode 200 a includes, at least the following steps:

S21, providing an active carbon nanotube (acCNT) film;

S22, soaking the acCNT film in a polymer monomer solution, adding an oxidant solution to the polymer monomer solution to generate a polymer coated acCNT film;

S23, providing a carbon nanotube (CNT) solution, and filtering the CNT solution through the polymer coated acCNT film to create an a CNT-polymer coated acCNT film; the CNT side of the CNT-polymer coated acCNT film is defined as S-side, and the polymer coated acCNT side is defined as P-side;

S24, coating the second material 233 a onto the P-side; and

S25, coating the first material 213 a onto the S-side.

In step S21, the active carbon nanotube (acCNT) is a carbon nanotube with a hydrophilic functional group. The active carbon nanotube can be created by heating and oxidizing carbon nanotube. In one embodiment, 30 mg of superaligned pure carbon nanotubes was heated in an air environment of 500° C. for 30 min to create an active superaligned carbon nanotubes (acSACNT).

The active carbon nanotubes are dispersed in a solution and filtered to form an active carbon nanotube film. In one embodiment, 30 mL of acSACNT was ultrasonically mixed with ethanol solution (1 mg/mL), and the mixture then filtered to create an acSACNT film.

In step S22, the polymer monomer solution can be created by dissolving a polymer monomer in a solvent. The oxidant solution can be created by dissolving an oxidant in a solvent. The oxidant can polymerize the polymer monomer to form a polymer. The polymer monomer can be aniline, thiophene, pyrrole, acrylonitrile, ethanol, propylene, styrene, chlorethylene, or combination thereof. The oxidant can be selected according to the polymer monomer, such as nitric acid, sulphuric acid, ammonium persulphate, or combination thereof. The solvent can be selected according to the polymer monomer or the oxidant, such as ethanol or methanol.

In one embodiment, the acCNT film is soaked in 40 mL of aniline/HCl aqueous solution (1 M HCl, 0.05 M aniline) at 0° C. for 10 min. Then 40 ml of 0.05 M (NH₄)₂S₂O₈ aqueous solution is slowly added into the aniline/HCl aqueous solution. The mixture is kept at 0° C. for 24 h to generate PANI coated acCNT (PANI@acSACNT) film. The PANI@acSACNT film can be cleaned with deionized water, ethanol and acetone, and then dried at 80° C. for 24 h.

In step S23, in one embodiment, 15 mL of SACNT/ethanol solution (1 mg/mL) is filtered through the PANI@acSACNT film, and then dried at 80° C. for 24 h to create an SACNT-PANI@acSACNT film.

In step S24, the second material 233 a can be supercapacitor electrolytes. In one embodiment, the second material 233 a is PVA electrolytes. 100 μL of PVA/H₂SO₄ aqueous solution (10 mg/mL PVA, 0.1 M H₂SO₄) is coated onto the P-side, dried at room temperature for 2 h.

In step S25, the first material 213 a can be the same as the cell packaging material of perovskite solar cell 100. In one embodiment, the first material 213 a is PMMA, the SACNT-PANI@acSACNT film is soaked in PMMA/toluene solution (10 mg/mL) for 30 min, and then dried at room temperature for 5 h. Then the PMMA is removed by acetone.

In step S3, the second solar cell surface 1002 and the first electrode surface 2001 a can be closely attached together.

In step S4, the liquid 300 dissolves and reshapes the cell packaging material and the second packaging material. The cell packaging material and the second packaging material can be the same material. In one embodiment, both the cell packaging material and the second packaging material can be PMMA, the liquid 300 is chlorobenzene. 100 μL of chlorobenzene is dropped onto the P-side of the first supercapacitor electrode 200 a to dissolve and reshape the portion of the PMMA film that is between the perovskite solar cell 100 and the first supercapacitor electrode 200 a.

In step S5, the first supercapacitor electrode 200 a and the second supercapacitor electrode 200 b together form a supercapacitor 200.

FIG. 3 shows an embodiment of a photocapacitor 10. The photocapacitor 10 includes a perovskite solar cell 100 and a supercapacitor 200.

The perovskite solar cell 100 includes a conductive glass layer 110, a blocking layer 130, and an absorbing layer 140. The blocking layer 130 is between the conductive glass layer 110 and the absorbing layer 140.

The conductive glass layer 110 further includes a conductive surface 111. In one embodiment, the conductive glass layer 110 is fluorine-doped tin oxide (FTO) glass.

The blocking layer 130 can transport electrons and block holes. The material of the blocking layer 130 can be TiO₂.

The absorbing layer 140 further includes a third carbon nanotube structure 141 and a perovskite structure 143. The perovskite structure 143 can be made of perovskite material, such as MAPbI₃.

The third carbon nanotube structure 141 is a layered structure which includes a first surface 1411 and a second surface 1412 opposite to the first surface 1411.

The third carbon nanotube structure 141 includes a plurality of third carbon nanotubes joined by van der Waals attractive force therebetween. Adjacent third carbon nanotubes form a plurality of third micropores. The third carbon nanotubes can be multi-walled carbon nanotubes.

The first surface 1411 is directly contacted with the perovskite structure 143, and some of the micropores near the first surface 1411 are filled with the perovskite material. The second surface 1412 is directly contacted with packaging material, and some of the micropores near the second surface 1412 are filled with the packaging material.

The supercapacitor 200 includes a first supercapacitor electrode 200 a and a second supercapacitor electrode 200 b opposite to the first supercapacitor electrode 200 a.

The first supercapacitor electrode 200 a further includes a first electrode structure 210 a and a second electrode structure 230 a stacked with each other.

The first electrode structure 210 a includes a first carbon nanotube structure 211 a and a first structure made of a first material 213 a, the first carbon nanotube structure 211 a includes a plurality of first carbon nanotubes joined by van der Waals attractive force therebetween. Adjacent first carbon nanotubes form a plurality of first micropores. Some of the first micropores are filled with the first material. The first carbon nanotubes can be superaligned pure carbon nanotubes. The first material can be PMMA.

The second electrode structure 230 a includes a second carbon nanotube structure 231 a and a second packaging structure made of a second material 233 a. The second carbon nanotube structure 231 a includes a plurality of second carbon nanotubes joined by van der Waals attractive force therebetween. Adjacent second carbon nanotubes form a plurality of second micropores. Some of the second micropores are filled with the second material. The second carbon nanotubes can be polymer coated active carbon nanotubes. The second material can be supercapacitor electrolytes.

The first supercapacitor electrode 200 a and the second supercapacitor electrode 200 b together form a supercapacitor 200.

In one embodiment, the structure of the second supercapacitor electrode 200 b is the same as the first supercapacitor electrode 200 a. The second supercapacitor electrode 200 b includes a first electrode structure 210 b and a second electrode structure 230 b stacked with each other.

The first electrode structure 210 b includes a first carbon nanotube structure 211 b and a first structure made of a first material 213 b, the first carbon nanotube structure 211 b includes a plurality of first carbon nanotubes joined by van der Waals attractive force therebetween. Adjacent first carbon nanotubes form a plurality of first micropores. Some of the first micropores are filled with the first material.

The second electrode structure 230 b includes a second carbon nanotube structure 231 b and a second packaging structure made of a second material 233 b. The second carbon nanotube structure 231 b includes a plurality of second carbon nanotubes joined by van der Waals attractive force therebetween. Adjacent second carbon nanotubes form a plurality of second micropores. Some of the second micropores are filled with the second material.

The photocapacitor 10 further includes a first external electrode 400, a second external electrode 500, and a third external electrode 600. The first external electrode 400 is connected to the conductive surface 111 of the perovskite solar cell 100, the second external electrode 500 is connected to the first carbon nanotube structure 211 a of the first supercapacitor electrode 200 a, and the third external electrode 600 is connected to the first carbon nanotube structure 211 b of the second supercapacitor electrode 200 b.

The photocapacitor 10 further includes a shell 700 which is used to packaging the perovskite solar cell 100 and the supercapacitor 200. The shell 700 can prevent the perovskite solar cell 100 and the supercapacitor 200 contact with the outside, especially water vapor. The material of the shell 700 can be PMMA.

FIG. 4 and FIG. 5 are voltage output performances of perovskite solar cell 100 and photocapacitor 10 under different illumination conditions, respectively. The photocapacitor 10 may have to work under complex illumination conditions, such as light, dark, and fluctuating sunlight.

Under lighted conditions, the voltage of perovskite solar cell 100 rises rapidly to 0.7 V, while the voltage of the photocapacitor 10 rises to 0.7 V after 80 s.

Under darkened conditions, the voltage of perovskite solar cell 100 rapidly down to 0 V, while the voltage of the photocapacitor 10 declined more slowly than the perovskite solar cell 100.

Under fluctuating sunlighted conditions, the voltage of the photocapacitor 10 is more stable than that of the perovskite solar cell 100.

The photocapacitors 10 can effectively improve the voltage output under different illumination conditions. The photocapacitors 10 is suitable for portable electronics.

The embodiments shown and described above are only examples. Even though numerous characteristics and advantages of the present technology have been set forth in the forego description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, including in matters of shape, size and arrangement of the parts within the principles of the present disclosure up to, and including, the full extent established by the broad general meaning of the terms used in the claims.

Depending on the embodiment, certain of the steps of methods described may be removed, others may be added, and the sequence of steps may be altered. The description and the claims drawn to a method may include some indication in reference to certain steps. However, the indication used is only to be viewed for identification purposes and not as a suggestion as to an order for the steps. 

What is claimed is:
 1. A photocapacitor, comprising: a supercapacitor comprising a first supercapacitor electrode; wherein the first supercapacitor electrode comprises a first electrode structure and a second electrode structure stacked with each other, the first electrode structure comprises a first carbon nanotube structure; a perovskite solar cell comprising an absorber layer, wherein the absorber layer comprises a third carbon nanotube structure and a perovskite structure, the third carbon nanotube structure comprises a first surface and a second surface opposite to the first surface, the first surface is directly contacted with the perovskite structure, and the second surface is directly contacted with the first carbon nanotube structure.
 2. The photocapacitor of claim 1, wherein the first carbon nanotube structure comprises a plurality of first carbon nanotubes, and adjacent first carbon nanotubes form a plurality of first micropores, some of the first micropores are filled with a first material.
 3. The photocapacitor of claim 2, wherein the first carbon nanotubes are superaligned pure carbon nanotubes.
 4. The photocapacitor of claim 2, wherein the first material is Polymethyl methacrylate.
 5. The photocapacitor of claim 1, wherein the second electrode structure comprises a second carbon nanotube structure comprising a plurality of second carbon nanotubes, adjacent second carbon nanotubes form a plurality of second micropores, and some of the second micropores are filled with a second material.
 6. The photocapacitor of claim 5, wherein the second carbon nanotubes are polymer coated active carbon nanotubes.
 7. The photocapacitor of claim 5, wherein the second material is supercapacitor electrolytes.
 8. The photocapacitor of claim 1, wherein the third carbon nanotube structure comprises a plurality of third carbon nanotubes, adjacent third carbon nanotubes form a plurality of third micropores.
 9. The photocapacitor of claim 8, wherein some of the third micropores near the first surface are filled with a perovskite material.
 10. The photocapacitor of claim 8, wherein some of the third micropores near the second surface are filled with a packaging material.
 11. The photocapacitor of claim 8, wherein the third carbon nanotubes are multi-walled carbon nanotubes.
 12. The photocapacitor of claim 1, wherein the perovskite solar cell further comprises a conductive glass and a block layer, and the block layer is between the conductive glass and the absorber layer.
 13. The photocapacitor of claim 12, wherein the conductive glass is fluorine-doped tin oxide glass.
 14. The photocapacitor of claim 12, wherein the block layer comprises titanium dioxide.
 15. The photocapacitor of claim 1, wherein the supercapacitor further comprises a second supercapacitor electrode opposite to the first supercapacitor electrode.
 16. The photocapacitor of claim 15, wherein the photocapacitor further comprises: a first external electrode connected to the perovskite solar cell; a second external electrode connected to the first supercapacitor electrode; and a third external electrode connected to the second supercapacitor electrode. 